The basic concept of neurosurgical procedures to treat spasticity is to decrease the hyperactivity of the stretch reflex. Selective peripheral neurotomy is a method to partially resect the peripheral motor nerve. The alpha motor and Ia afferent nerves are resected, but the latter is essential owing to its lasting effect in reducing spasticity. Focal spasticity in adult patients can be effectively treated using peripheral neurotomy. Functional posterior rhizotomy, mostly used to treat paraplegic spasticity in children with cerebral palsy, involves the sectioning of posterior rootlets associated with abnormal motor responses to electrical stimulation. Intrathecal baclofen therapy is useful in treating diffuse spasticity. Baclofen inhibits the activity of alpha motor neurons both pre and post synaptically at the level of the spinal cord. A decrease in Hmax/Mmax in the H-reflex electrophysiologically represents the effectiveness of these procedures. Good clinical results can be achieved by appropriate indication depending on the clinical features of spasticity in each patient.